1. Field of the Invention
This invention relates to an isolated animal caging system in which a lockable removable internal sterile water valve is prevented from leaking into the animal cage.
2. Description of the Related Art
Watering devices for supplying water from an outside watering system to an animal confined in a cage are known in the art. U.S. Pat. No. 4,699,088 issued to the same inventors of this disclosure describes a cage assembly including a water manifold for allowing confined animals to be supplied with water from an outside watering system. The cages can be positioned on a rack. A watering valve is inserted into the water aperture through a pliable, flexible entrance which seals the cage when the cage assembly is disconnected from the outside watering source. However, this cage assembly has the disadvantage that the watering valve does not stay with the cage when the cage is removed from the rack. Accordingly, the watering valve must be sterilized each time it is inserted into a cage in order to maintain a sterile cage condition.
U.S. Pat. No. 4,365,590 relates to an animal cage and rack system in which each cage is stored adjacent to an outside water valve. The animal has access to the valve through an aperture in the cage. A v-shaped trough positioned on the outside of the cage below the valve collects excess dripping water from the valve. This watering system has the disadvantage that the valve is positioned outside the cage and cannot be assured of a sterile valve condition to the animal.
U.S. Pat. No. 5,042,429 describes a drinking valve fastened within a cage to allow an animal to consume liquid from an outside liquid manifold. A friction fit coupling allows the internal drinking valve to be connected and removed from the liquid manifold when the cage is respectively inserted or removed from a rack. The drinking valve remains with the cage when the cage is removed from the water manifold for maintaining a barrier condition and allowing sterilization of the valve within the cage. Progressive wear of the valve or a malfunction can cause the valve to leak into the cage. The leaking of the valve can cause wetting of the bedding in the cage. If the water valve continues to leak, the cage can fill up with water resulting in serious harm or death to the confined test animal.
U.S. Pat. No. 4,284,036 describes a watering system for fowl and small animals including a water valve which engages two spaced valve seats. The valve seats are unseated by movement laterally and upwardly of a pin extending through a discharge opening to ensure effective sealing of the valve. However, wear of the valve seats can result in water leaking into the cage.
Of possible general relevance are U.S. Pat. No. 4,881,569 related to a coupling for a drinking water supply and U.S. Pat. No. 4,458,632 related to a water dispenser for small animals.